#!/usr/home/elb/ruby-1.6.6/ruby
#!/usr/bin/env ruby
#!/usr/local/bin/ruby

# Copyright 2002 Blossom Associates West
# All rights reserved.

# Converts from comma separated values to tab separated values.
# Leaves quoted commas undisturbed.
# BUG: Gets out of step with errors in input like quote marks where they shouldn't be.
# BUG: Preserves spaces after commas.
# Eric Blossom

class ParserState
  def initialize( &action )
    super()
    @action = action
  end
  def charArrived( c )
    @action.call( c );
  end
end

# Define empty states so that we can refer to them.
ourState = nil
inQuoteState = nil
escapeState = nil

startState = ParserState.new() { |c|
  case c.chr 
  when ','
    STDOUT.putc( "\t" )
  when '"'
    ourState = inQuoteState
  else
    STDOUT.putc( c )
  end
}

inQuoteState = ParserState.new() { |c|
  case c.chr 
  when '"'
    ourState = startState
  when "\n"
    STDOUT.putc( c )
    ourState = startState # Recover from unfinished quote.
  when "\\"
    ourState = escapeState
  else
    STDOUT.putc( c )
  end
}

escapeState = ParserState.new() { |c|
  case c.chr 
  when "\\"
  when "\""
  else
    STDOUT.putc( "\\" )
  end
  STDOUT.putc( c )
  ourState = inQuoteState
}

ourState = startState

while ( c = STDIN.getc )
  ourState.charArrived( c )
end